Clinical usefulness of wave intensity analysis

Abstract

Wave intensity (WI) is a hemodynamic index, which can evaluate the working condition of the heart interacting with the arterial system. It can be defined at any site in the circulatory system and provides a great deal of information. However, we need simultaneous measurements of blood pressure and velocity to obtain wave intensity, which has limited the clinical application of wave intensity, in spite of its potential. To expand the application of wave intensity in the clinical setting, we developed a real-time non-invasive measurement system for wave intensity based on a combined color Doppler and echo-tracking system. We measured carotid arterial WI in normal subjects and patients with various cardiovascular diseases. In the coronary artery disease group, the magnitude of the first peak of carotid arterial WI (W 1 ) increased with LV max. dP/dt (r = 0.74, P \ 0.001), and the amplitude of the second peak (W 2 ) decreased with an increase in the time constant of LV pressure decay (r = -0.77, P \ 0.001). In the dilated cardiomyopathy group, the values of W 1 were much lower than those in the normal group (P \ 0.0001). In the hypertrophic cardiomyopathy group, the values of W 2 were much smaller than those in the normal group (P \ 0.0001). In mitral regurgitation before surgery, W 2 decreased or disappeared, but after surgery W 2 appeared clearly. In the hypertension group, the magnitude of reflection from the head was considerably greater than that in the normal group (P \ 0.0001). We also evaluated hemodynamic effects of sublingual nitroglycerin in normal subjects. Nitroglycerin increased W 1 significantly (P \ 0.001). WI can be obtained non-invasively using an echo-Doppler system in the clinical setting. This method will increase the clinical usefulness of wave intensity.

Arterial hemodynamics and wave analysis in the frequency and time domains: an evaluation of the paradigms

“…The characteristics of such a wave traveling through an elastic tube are nicely demonstrated in this issue by Jiun-Jr Wang and co-workers [22]. The wave intensity theory has already ignited a series of clinical studies and resulted in a device for analyzing the interaction between the cardiac and arterial system which is discussed by Motoaki Sugawara [14].…”

Evaluation of carotid wave intensity in firefighters following firefighting

“…A detailed prescription of the methodology has been published previously (Sugawara et al 2009;Niki et al 2002). Reproducibility and variability of WI indices has been reported to be clinically acceptable Liu et al 2011).…”

Importance of Arterial Conduit Function Assessment in Chronic Congestive Heart Failure: Predictors of True Circulatory Decompensation for Optimal Timing of Mechanical Circulatory Support

“…[40] In 2001 we first studied 31 patients suffering from end stage DCM [41] to assess circulatory reserves by utilizing a simple tilting test moving patients from supine to upright position. When DCM patients moved from supine to upright position, the filling of the venous bed was reduced (the overdistended jugular vein was collapsed) and filling of the heart chambers was therefore also reduced.…”